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By Hematian J

A high horizontal stress field has significant effect on the stability of underground roadways and influences the design of a support system in this environment. The high horizontal stresses at E1lalong Colliery, NSW, Australia provided the environment for this study. Samples of coal measures 'rock were collected and tested to determine their mechanical properties. The lithology, stress state, geometry and conditions prevailing in particular areas of the mine were obtained from geotechnical reports available at the mine and by field observation. The results of a series of finite element models constructed and tested under various conditions provided a basis for comparison with field observations. Analysis of the results indicated sufficient correspondence to provide a basis for the proposed design of an optimum support system. It is not suggested that finite analysis provides 'exact answers', but it does show the relative importance and interaction of various parameters.

Jan 1, 1995

The need for formalised geotechnical reporting has not been fully explored at many operations. With the continuing need to provide safer and more efficient workplaces, the requirement for good geotechnical reporting systems (as with other reporting systems) has become of greater importance.Historically, the risk from rockfalls has been the largest cause of fatal injuries in the underground mining industry. The response of the ground to mining is generally poorly documented at many mines. At Olympic Dam, it was found that the existing corporate hazard and incident reporting (HIR) procedure did not record enough specifics about geotechnical issues. A separate and more specific geotechnical reporting process was set up to address this problem.This paper examines the role that geotechnical reporting plays at the WMC Resources Olympic Dam Mine; from reporting and rectifying day-to-day geotechnical issues that affect the operation to documenting and analysing longer term trends.

Jan 1, 2004

EIA is a test of a development proposalÆs legitimacy and asks two questions: not only æis the proposal competent?Æ but also ædoes the proposal have moral authority?Æ For reasons of miningÆs historic importance and of a scientific and technological industry culture, traditional EIA has focussed on the first on these, an increasingly misplaced priority in a changing world.This paper explains why competence alone is not enough and examines the second of the two questions: what is meant by a projectÆs moral authority, why does it matter, why has it taken so long to become an issue and what, in practical terms, can project proponents do about it.

Jan 1, 2004

By G D. McDonald

Flinders Mines is an ASX300 iron ore explorer and developer with a tenement package located in the Hamersley Ranges region of Western Australia, approximately 70 km north of Tom Price. Exploration over the past three years has identified a Global Resource in excess of 740 Mt at a grade of 55.4 per cent Fe (+50 per cent Fe cut-off). This resource is spread across multiple deposits and has been divided into a number of mineralisation type domains based on geometallurgical and geochemical boundaries. These domains are comprised of transported haematite rich detrital iron deposits (DID) and goethite dominant Channel iron deposits (CID) as well as in situ bedded Brockman iron deposits (BID). On the basis of differences in physical and chemical characteristics, the DID have been divided into four discrete units. The four DID units form a stratigraphic sequence with the iron grade increasing and the contaminant concentrations decreasing with depth. The upper DID unit is lower grade and currently unlikely to provide a marketable product, without signifi cant beneficiation. The lower three DID units, together with the CID and BID, are of a higher quality and have the potential to yield marketable ore. The ability to define and recognise these different units has resulted in a more reliable and robust geological interpretation and hence greater confidence in the resulting resource model. This has been evident in the excellent conversion of inferred to indicated resources.

Jul 11, 2011

The 250 metric tonnes of gold and 360 000 metric tonnes of copper recovered from the Mt Morgan Mine in Central Queensland justify its fame. The mine ceased operation before the advent of three-dimensional computer graphical modelling of orebodies became common practice in mine planning. The Mount Morgan Mine records however remain and are the database for this study. The Mount Morgan project takes ore deposit modelling one step further by examining the relationship between grade distribution within the orebody and key geological features, as a tool for exploration and development.The Mount Morgan gold and copper mineralisation is shown to be strongly lognormally distributed. The deposit has been split into three areas, using geological boundaries, each with different geostatistical characteristics. Important features include: the spatial relationship of near-vertical, high grade shoots with a ring dyke thought to be related to the North Dyke; separation of the high grade eastern stopes from the others along the Andesite Dyke; and lack of concentrated mineralisation along the Slide Fault.Recognition of these features is useful to those currently exploring the Mount Morgan district for similar style deposits, by stressing the importance, or lack thereof, of the geological features.

Jan 1, 1993

By Y Chung, B Choi, H Lee

Numerous studies have explored refractory corrosion in the presence of slag and/or metal, utilising the Finger Rotating Test (FRT). Recent experimental results revealed that corrosion initially increased with rising rotation velocity but was then suppressed above a critical rotating speed, under conditions involving a two-liquid solution of slag and molten steel. This phenomenon indicated that the liquid/liquid interface movement occurred during spindle rotor. However, understanding of the phenomenon, known as the rod climbing effect, remains inadequate in the case involving slag, molten steel and refractories. To gain deeper insights, a simulation experiment was conducted on the phenomenon using silicon oil/water and the phenomenon was analysed using computerised simulation software (Ansys Fluent). Experimental modelling demonstrated that interfacial movement occurs even at low rotation velocity, as low as 200 rev/min, when the viscosity of silicone oil is at 100 cP. Computational analysis utilising the Volume of Fluid (VOF) method and a realisable k-ε turbulence model elucidated that interface elevation during rotor rotation arises due to viscosity disparities between the two fluids. Furthermore, this movement is more pronounced when the viscosity difference is lower. Additionally, the study findings suggest that higher density differences between two liquids suppress the phenomenon of interface movement.

Jun 19, 2024

By M Zoorabadi

Overcoring is a common technique to measure in situ rock stress using the concept of stress relief. The strains measured during overcoring are used to calculate the stress tensor assuming continuous, homogeneous, isotropic and linear elastic behaviour. This approach does not recognise any effect of the thickness of the rock annulus produced during overcoring instead assuming that the stresses are entirely a function of the difference in strain between the start of the overcoring and the end with no regard to the transient strains produced. Three-dimensional numerical modelling was used to simulate the overcoring process and investigate the impact of core diameter on the transient stresses and strains during overcoring. This study showed that in thicker core, maximum transient axial stresses and strains occur when the drill bit approaches the measuring point and greater tensile axial stresses were produced when the annulus was thinner. CITATION:Zoorabadi, M, 2018. Numerical study of annulus thickness on overcoring stress measurements, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 274–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By R Jia, J T. Waldram

"The Caijiaying lead zinc mine is located in China, north-west of Beijing, in Hebei Province. The region experiences severe winters, below -35°C, and warm summers, up to 30°C. The mine and concentrator commenced operations in the second half of 2005 with a conventional tailings disposal system consisting of a tailings dam with peripheral ring main discharge and central water recovery. A second similar dam sharing one common wall was added later. In view of the extreme winter conditions tailings lines and ring mains plus spigots, together with return water lines, require insulation and electrical trace heating. The volume of process water trapped as ice in the tailings dam ponds each winter is significant. This seasonal variation presents a major difficulty in the management of process water availability. Although Caijiaying is an underground mine there was no backfill plant at the start of operations. As plant throughput increased more quickly than originally anticipated, tailings storage capacity became a prime concern. The construction of a backfill plant in 2007 reduced the pressure on surface tailings storage area requirements, but as suitable land on which to construct further tailings storage was both expensive and difficult to acquire, a more efficient use of the available area was required. Dry tailings storage, where flotation tailings are filtered to provide an immediate return of process water plus ‘dry’ tailings filter cake for stacking, provided an answer to both the land area required, and the water management difficulties. The paper details the reasoning behind the change and the benefits obtained at Caijiaying by moving from ‘wet’ tailings storage to ‘dry’ tailings storage.Citation:Waldram, J T and Jia, R, 2016. Caijiaying Dry Tailings Storage, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 379–382 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By C Linklater, J Chapman, A Watson

Closure options under consideration at some sites include backfilling mined-out pits with waste rock. Backfill may include mineralised and non-mineralised waste rock. Following groundwater rebound, flow-through conditions may develop in the pit post-closure. The backfill located in the saturated zone below the water table may release solutes under such conditions. It is therefore important to understand the potential impacts that backfilled pits could have on postclosure groundwater quality.Geochemical characterisation programs are the foundation for assessing the potential chemistry of water that has contacted mined wastes. Such programs must be designed to obtain data relevant to the closure options under consideration. To complement standard testing techniques, SRK utilises saturated column testing designed to generate data on leaching rates under anoxic conditions that could be encountered within submerged backfill.This paper presents the findings of saturated column test work carried out on waste rock samples from an iron ore mine in the Pilbara.CITATION:Watson, A, Linklater, C and Chapman, J, 2016. Backfilled pits – laboratory-scale tests for assessing impacts on groundwater quality, in Proceedings Life-of-Mine 2016 Conference , pp 110–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By D Abbott

Mining in Western Australia places significant economic and environmental responsibility on Government and the mining industry. Groundwater abstraction is regulated by the Department of Water. The Department has recently issued a guideline for Pilbara mines, and this paper focuses on the Pilbara for its examples and studies. The guideline is intended to form the basis for developing a statewide policy, consistent with reporting and assessment policy.With rapid expansion of the mining industry between 2005 and 2008, the groundwater resources in the Pilbara region of the State are under increasing pressure. Significant new management and regulatory issues arising recently include: cumulative impact assessment; disposal of dewatering excess by discharge, sharing or reinjection; life-of-mine approvals and closure planning; closure water quality including metals concentration in pit lakes; and in situ leaching mining methods and their impacts on regional water resources (and change of State Government Policy with respect to uranium mining).

Jan 1, 2009

The purpose of this study was to investigate the effectiveness of froth fl otation for the recovery of gold from the gravity tailing stream of the former Lihir Gold Limited (LGL) operation in Ballarat. The P80 of the tailings was determined by screen analysis as 1 mm, with test work conducted on as received material along with samples ground to P80 sizes of 47, 78 and 134 microns. Laboratory scale batch flotation tests were conducted at both natural and elevated pH to investigate the impact of pyrite depression on gold recovery. Results indicated that although an increase in grade from approximately 0.7 g/t to 3 g/t was achievable at a natural pH and a P80 of 134 micron, gold recovery was low at just 35 per cent. Finer grind sizes were found to have an adverse effect on both grade and recovery. Future efforts will be focused on the sub 310 micron size fraction of the tailings, which was revealed to contain approximately 85 per cent of the available gold and may be amenable to cyanidation or ultra-fine gravity treatment.

Aug 1, 2010

A laminar-flow furnace was used to study the combustion of four flotation concentrates (chalcopyrite, pyrite, galena, and sphalerite) in air at temperatures up to 1400¦C. A special- Iv developed two-colour pyrometer was used to measure the temperature of individual chalco- pvrite and pyrite particles as they underwent combustion. Chalcopyrite and pyrite ignited with very high rates of reaction at air tempera- tures above 480 and 600¦C respectively, forming molten products. Galena and sphalerite required temperatures in excess of 700 and 1200¦ respect- ively to attain equivalent rates of reaction. The high rates of reaction for galena and spha- lerite were caused by vaporization. Temperature measurements for chalcopyrite and pyrite are reported here, together with vaporization measurements for chalcopyrite, galena, and Sphalerito

Jan 1, 1980

By W B. Edgar, S C. Dominy

High-nugget effect vein-gold systems are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of Ore Reserves at production start-up. However, despite the well-known risks, these deposits often have a grade upside that makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The use of the grade estimate supported by a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion based estimates through to data-based estimates and geostatistical conditional simulation. Whichever method used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties.CITATION:Dominy, S C and Edgar, W B, 2012. Approaches to reporting grade uncertainty in high-nugget gold vein projects, in Proceedings Project Evaluation 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

Caving is the lowest cost underground mining method, provided that drawpoint spacing, drawpoint size and ore handling facilities are designed to suit the caved material and that the drawpoint horizon can be maintained for the draw life. In the near future several open pit mines that produce in excess of 50 000 tons per day will have to examine the feasibility of converting to low cost, large scale underground operations. Several other large scale, low grade underground operations will experience major changes in their mining environments as large dropdowns are implemented. These changes demand a more realistic approach to mine planning than has occurred in the past, where existing operations have been projected to increased depths with little consideration of the change in mining environment that will occur. As economics force the consideration of underground mining of large, competent orebodies by low cost methods, the role of cave mining will have to be defined. In the past caving has generally been considered for rock masses that cave and fragment readily. The ability to define cavability and fragmentation, the availability of large, robust LHDs, a better understanding of draw control requirements, improved drilling equipment for secondary blasting and reliable cost data have shown that competent orebodies with coarse fragmentation can be exploited by cave mining at a much lower cost than with drill and blast Methods.

Jan 1, 1995

The scope of this paper has been restricted to the manufacture in Australia of seamless steel tubing, as the subject of buttweld tubing has already been dealt with by A. N. Hamilton in a paper delivered before the Institute in 1935.The earliest attempts to produce seamless steel tubes were based on the extrusion of lead piping, a process developed by Thomas Burr in 1820. However, the problems associated with the extrusion of white hot steel had to await the metallurgical knowledge of the twentieth century, and these early attempts were unsuccessful.The years 1840 and 1845 were noteworthy for the introduction of the first practical methods of making seamless steel tubes. In one process, a large circular plate was 'cupped' in a vertical press; in the other, a round steel billet was pierced for its entire length.The product from both these methods was then elongated by repeated reheating and rolling over an internal mandrel, in a circular pass mill.At this juncture, it should be noted that every process developed for the manufacture of seamless steel tubing can be divided into two parts. In the first part of the process, attention is centred on the conversion of the heated bloom into a short, thick-walled, hollow cylindrical forging; this product is then elongated in the second section of the process. It will be noted that these two sections are actually quite distinct, and in practice numerous methods exist for carrying out both functions. The first stage is generally referred to as 'piercing', the second stage being termed 'elongating.' In this paper, the author proposes to outline the various methods adopted for piercing and elongating; the reader is asked to note that although certain methods of piercing are almost invariably associated with only one method of elongating, the distinction between the two functions is, nevertheless, a vital one and should be noted accordingly.

Jan 1, 1947

This paper describes modern long-term mine scheduling and gives an example of its application. It then discusses the obstacles to the implementation of such schedules.

Sep 26, 2011

By Warner RE

SINCE 1952, when Elliott et a/ first applied the Sherwood correlation for flooding in chemical absorption towers to blast furnaces numerous investigators throughout the world have followed their example and much research effort has been spent to tighten the correlation and recently to extend investigation of flooding to side gas entry conditions. The widespread use of the Sherwood concept of flooding has been such that even the word itself has become an integral part of blast furnace nomenclature. The evidence for the applicability of Sherwood's relationship has been that the flooding limits calculated from blast furnace parameters lie approximately on the Sherwood line. However, the values of many of the variables for the blast furnace calculation are only estimates and at first sight one may wonder at such 'close' coincidence when some of the estimated parameters entering the Sherwood correlation are raised to the power of three or more, as for the bed porosity and the liquid surface tension. It is felt that the explanation of this result lies in the logarithmic: nature of the plot and/or the fortuitous can- cellation of the errors of the estimates in the calculations coupled with the fact that blast furnace fluid ratios lie within a very narrow range of values. The foregoing considerations should in their own right place doubt on the correctness of the Sherwood type flooding correlation applied to the blast furnace. Additional doubt regarding the existence of the Sherwood type flooding in the furnace has been cast by the results obtained in the Tokyo University experimental blast furnace. From the reasoning of both Standish and Colquhoun (p. 20) and Warner (p. 23) it is deduced that flooding in the traditional sense will only normally occur in the upper bosh (somewhere near the mantle), following softening as discussed by Palella et a/ on p. 75, and flooding in that zone is likely to result in furnace irregularity. On the other hand, the concept developed by Warner of slag hold-up above the raceways as a stable phenomenon not affecting furnace regularity is a process unique to the blast furnace and is not described by the Sherwood flooding theory. Recognising the considerable practical implications of slag hold-up above the raceways, this note further explores the physical process of slag hold-up. We envisage that bed of coke above the raceways in almost all blast furnaces would contain some slag held up by the gas pressure gradient. In general the slag would be contained in a ring and gas would bubble through in its ascent through the furnace. The force supporting this slag is the pressure gradient and obviously -much of the blast pressure is dissipated in supporting this structure.

Jan 1, 1975

By A Tsoy

This abstract describes long-term mining schedule optimisation approach that may be suitable for complex marginal projects and is based on modern scheduling techniques. CITATION: Tsoy, A, 2018. Strategic mine schedule optimisation, in Proceedings Complex Orebodies Conference 2018, pp 91–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By C Quirion

Agnico-Eagle Mines Limited, Laronde Division, operates the deepest single-lift shaft in the western hemisphere. The initial Penna hoisting plant was designed for a production rate of 1800 tonnes per day (t/d) from a 2240 m deep shaft. Exploration success, while sinking the shaft, led to a decision in 1998 to increase the production rate to 4500 t/d of ore from a loading depth of 2200 m. The new production rate was achieved by increasing the size of the rope and reducing the rope static factor from the existing 5.0 required by regulation to a static factor using the formula 25 000/(4000 + L) contained in a draft document that would eventually become SABS 0294 in South Africa. The formula permits Laronde to use a static factor as low as 4.0. The upgraded Penna hoisting system is the first hoisting plant outside of South Africa to meet the South African requirements. This paper describes the conversion of the hoisting plant to the lower rope selection factor in the year 2000 and the operating and maintenance issues experienced since then.

Jan 1, 2005

The planned extraction of deeper copper ore at Isa Mine has necessitated a review of existing equipment and methods to contain costs and improve working conditions. Mining is in progress for a crushing-conveying system to serve the deeper southern areas of the 1100 Orebody. This system will permit direct tipping of ore to the crushers and conveying of the crushed ore by cable belt conveyor to existing shaft loading facilities, a distance of about 2 km. To develop part of the conveyor drive a new machine will be used, the Robbins MM120 Mobile Miner, a joint development project between The Robbins Company and Mount Isa Mines Limited. The Mobile Miner uses a rotating cutting wheel to excavate headings 3.7 m high and from 4.7 m to 7.5 m wide. To ventilate the deep crusher complexes and associated development at high virgin rock temperatures, a refrigeration plant will be built on surface to reticulate chilled water underground. Bulk cooling of air to the 3000/3500 Orebodies and the southern crushers will be combined with the reticulation of chilled service water to the lower workings of the mine.

Jan 1, 1984